Hi,
Why do Class D amplifier designers prefer high voltage supply rails?
Please find attached here two Full-Bridge , Class D amplifier simulations which run in the free simulator called LTspice by linear.com.
Each simulation is of a 4KHz sine wave which gives 100W of power in the speaker.
One of the Class D amplifiers has an 80V rail and the other has a 40V rail.
Each simulation gives the same output signal (i.e. the same current in the speaker)
……so why do engineers prefer higher voltage rails for Class D amplifiers?……….
……because these simulations show that you can get just the same speaker signal with a lower rail voltage…… and simply using a lower value of filter inductor.
(To run these simulations , you will need to make sure that the text files called “sin” and “sin1” are situated in the same folder as the LTspice simulations.)
Also, do you know if my representation of the speaker as an 8 Ohm load is correct?…..Does it have an inductance associated with it?…….is this inductance likely to be poorly toleranced.?
Below are the simulation files and the text files which must be placed in the same folder as the simulation files.
...i think the upload site has converted them into html files , so you would need to copy and paste the content into a text file in each case and save it as .txt
...The simulation files should be pasted into a text file, but instead of saving it as .txt type, you need to save it as a .asc file, or else it won't run in the LTspice simulator
40V, 100W Full bridge class D amplifier simulation:
CLASS D _40V 100W.asc download - 2shared
80V, 100W Full bridge class D amplifier simulation:
CLASS D _80V 100W.asc download - 2shared
Text file which must accompany simulations:
sin.txt download - 2shared
Another Text file which must also accompany simulations:
sin1.txt download - 2shared
attachments again, just in case above not good (the text files sin and sin1 wouldnt upload here as too big
View attachment CLASS D _40V 100W.asc
View attachment CLASS D _80V 100W.asc
Why do Class D amplifier designers prefer high voltage supply rails?
Please find attached here two Full-Bridge , Class D amplifier simulations which run in the free simulator called LTspice by linear.com.
Each simulation is of a 4KHz sine wave which gives 100W of power in the speaker.
One of the Class D amplifiers has an 80V rail and the other has a 40V rail.
Each simulation gives the same output signal (i.e. the same current in the speaker)
……so why do engineers prefer higher voltage rails for Class D amplifiers?……….
……because these simulations show that you can get just the same speaker signal with a lower rail voltage…… and simply using a lower value of filter inductor.
(To run these simulations , you will need to make sure that the text files called “sin” and “sin1” are situated in the same folder as the LTspice simulations.)
Also, do you know if my representation of the speaker as an 8 Ohm load is correct?…..Does it have an inductance associated with it?…….is this inductance likely to be poorly toleranced.?
Below are the simulation files and the text files which must be placed in the same folder as the simulation files.
...i think the upload site has converted them into html files , so you would need to copy and paste the content into a text file in each case and save it as .txt
...The simulation files should be pasted into a text file, but instead of saving it as .txt type, you need to save it as a .asc file, or else it won't run in the LTspice simulator
40V, 100W Full bridge class D amplifier simulation:
CLASS D _40V 100W.asc download - 2shared
80V, 100W Full bridge class D amplifier simulation:
CLASS D _80V 100W.asc download - 2shared
Text file which must accompany simulations:
sin.txt download - 2shared
Another Text file which must also accompany simulations:
sin1.txt download - 2shared
attachments again, just in case above not good (the text files sin and sin1 wouldnt upload here as too big
View attachment CLASS D _40V 100W.asc
View attachment CLASS D _80V 100W.asc
Last edited:
Hi,
the diyaudio forum attachment facility wont upload the text files as it says they are too big.
I have uploaded them to the 2shared.com website, but when i checked if i could download them, it wanted me to install some software, i did this, and still dont seem to be able to view the text files.
The biggest text file is 564KB,
Does any reader know of a website which will upload this size file without the downloading person needing to install software?
actually all the files can be downloaded from here
http://www.edaboard.com/thread248650.html
the diyaudio forum attachment facility wont upload the text files as it says they are too big.
I have uploaded them to the 2shared.com website, but when i checked if i could download them, it wanted me to install some software, i did this, and still dont seem to be able to view the text files.
The biggest text file is 564KB,
Does any reader know of a website which will upload this size file without the downloading person needing to install software?
actually all the files can be downloaded from here
http://www.edaboard.com/thread248650.html
Last edited:
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